Bugfix: Improve Ready and Health Checks

ocis-pkg/handlers/checker.go

@@ -0,0 +1,117 @@
+package handlers
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"maps"
+	"net/http"
+
+	"golang.org/x/sync/errgroup"
+
+	"github.com/owncloud/ocis/v2/ocis-pkg/log"
+)
+
+// check is a function that performs a check.
+type check func(ctx context.Context) error
+
+// CheckHandlerConfiguration defines the configuration for the CheckHandler.
+type CheckHandlerConfiguration struct {
+	logger        log.Logger
+	checks        map[string]check
+	limit         int
+	statusFailed  int
+	statusSuccess int
+}
+
+// NewCheckHandlerConfiguration initializes a new CheckHandlerConfiguration.
+func NewCheckHandlerConfiguration() CheckHandlerConfiguration {
+	return CheckHandlerConfiguration{
+		checks:        make(map[string]check),
+		limit:         -1,
+		statusFailed:  http.StatusInternalServerError,
+		statusSuccess: http.StatusOK,
+	}
+}
+
+// WithLogger sets the logger for the CheckHandlerConfiguration.
+func (c CheckHandlerConfiguration) WithLogger(l log.Logger) CheckHandlerConfiguration {
+	c.logger = l
+	return c
+}
+
+// WithCheck sets a check for the CheckHandlerConfiguration.
+func (c CheckHandlerConfiguration) WithCheck(name string, f check) CheckHandlerConfiguration {
+	if _, ok := c.checks[name]; ok {
+		c.logger.Panic().Str("check", name).Msg("check already exists")
+	}
+
+	c.checks[name] = f
+	return c
+}
+
+// WithLimit limits the number of active goroutines for the checks to at most n
+func (c CheckHandlerConfiguration) WithLimit(n int) CheckHandlerConfiguration {
+	c.limit = n
+	return c
+}
+
+// WithStatusFailed sets the status code for the failed checks.
+func (c CheckHandlerConfiguration) WithStatusFailed(status int) CheckHandlerConfiguration {
+	c.statusFailed = status
+	return c
+}
+
+// WithStatusSuccess sets the status code for the successful checks.
+func (c CheckHandlerConfiguration) WithStatusSuccess(status int) CheckHandlerConfiguration {
+	c.statusSuccess = status
+	return c
+}
+
+// CheckHandler is a http Handler that performs different checks.
+type CheckHandler struct {
+	conf CheckHandlerConfiguration
+}
+
+// NewCheckHandler initializes a new CheckHandler.
+func NewCheckHandler(c CheckHandlerConfiguration) *CheckHandler {
+	c.checks = maps.Clone(c.checks) // prevent check duplication after initialization
+	return &CheckHandler{
+		conf: c,
+	}
+}
+
+// AddCheck adds a check to the CheckHandler.
+func (h *CheckHandler) AddCheck(name string, c check) {
+	h.conf.WithCheck(name, c)
+}
+
+func (h *CheckHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	g, ctx := errgroup.WithContext(r.Context())
+	g.SetLimit(h.conf.limit)
+
+	for name, check := range h.conf.checks {
+		checker := check
+		checkerName := name
+		g.Go(func() error { // https://go.dev/blog/loopvar-preview per iteration scope since go 1.22
+			if err := checker(ctx); err != nil { // since go 1.22 for loops have a per-iteration scope instead of per-loop scope, no need to pin the check...
+				return fmt.Errorf("'%s': %w", checkerName, err)
+			}
+
+			return nil
+		})
+	}
+
+	status := h.conf.statusSuccess
+	if err := g.Wait(); err != nil {
+		status = h.conf.statusFailed
+		h.conf.logger.Error().Err(err).Msg("check failed")
+	}
+
+	w.Header().Set("Content-Type", "text/plain") // fixMe: should be application/json!?!
+	w.WriteHeader(status)
+
+	if _, err := io.WriteString(w, http.StatusText(status)); err != nil { // io.WriteString should not fail, but if it does, we want to know.
+		h.conf.logger.Panic().Err(err).Msg("failed to write response")
+	}
+}

ocis-pkg/handlers/checker_test.go

@@ -0,0 +1,29 @@
+package handlers_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/owncloud/ocis/v2/ocis-pkg/handlers"
+)
+
+func TestCheckHandler_AddCheck(t *testing.T) {
+	c := handlers.NewCheckHandlerConfiguration().WithCheck("shared-check", func(ctx context.Context) error { return nil })
+
+	t.Run("configured checks are unique once added", func(t *testing.T) {
+		defer func() {
+			if r := recover(); r != nil {
+				t.Errorf("checks should be unique, got %v", r)
+			}
+		}()
+
+		h1 := handlers.NewCheckHandler(c)
+		h1.AddCheck("check-with-same-name", func(ctx context.Context) error { return nil })
+
+		h2 := handlers.NewCheckHandler(c)
+		h2.AddCheck("check-with-same-name", func(ctx context.Context) error { return nil })
+
+		fmt.Print(1)
+	})
+}

ocis-pkg/handlers/checknats.go

@@ -0,0 +1,23 @@
+package handlers
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nats-io/nats.go"
+)
+
+// NewNatsCheck checks the reachability of a nats server.
+func NewNatsCheck(natsCluster string, options ...nats.Option) func(context.Context) error {
+	return func(_ context.Context) error {
+		n, err := nats.Connect(natsCluster, options...)
+		if err != nil {
+			return fmt.Errorf("could not connect to nats server: %v", err)
+		}
+		defer n.Close()
+		if n.Status() != nats.CONNECTED {
+			return fmt.Errorf("nats server not connected")
+		}
+		return nil
+	}
+}

ocis-pkg/handlers/checktcp.go

@@ -0,0 +1,24 @@
+package handlers
+
+import (
+	"context"
+	"net"
+	"time"
+)
+
+// NewTCPCheck returns a check that connects to a given tcp endpoint.
+func NewTCPCheck(address string) func(ctx context.Context) error {
+	return func(_ context.Context) error {
+		conn, err := net.DialTimeout("tcp", address, 3*time.Second)
+		if err != nil {
+			return err
+		}
+
+		err = conn.Close()
+		if err != nil {
+			return err
+		}
+
+		return nil
+	}
+}

ocis-pkg/service/debug/option.go

@@ -20,9 +20,9 @@ type Options struct {
 	Token                string
 	Pprof                bool
 	Zpages               bool
-	Health               func(http.ResponseWriter, *http.Request)
-	Ready                func(http.ResponseWriter, *http.Request)
-	ConfigDump           func(http.ResponseWriter, *http.Request)
+	Health               http.Handler
+	Ready                http.Handler
+	ConfigDump           http.Handler
 	CorsAllowedOrigins   []string
 	CorsAllowedMethods   []string
 	CorsAllowedHeaders   []string
@@ -97,21 +97,21 @@ func Zpages(z bool) Option {
 }
 
 // Health provides a function to set the health option.
-func Health(h func(http.ResponseWriter, *http.Request)) Option {
+func Health(h http.Handler) Option {
 	return func(o *Options) {
 		o.Health = h
 	}
 }
 
 // Ready provides a function to set the ready option.
-func Ready(r func(http.ResponseWriter, *http.Request)) Option {
+func Ready(r http.Handler) Option {
 	return func(o *Options) {
 		o.Ready = r
 	}
 }
 
 // ConfigDump to be documented.
-func ConfigDump(r func(http.ResponseWriter, *http.Request)) Option {
+func ConfigDump(r http.Handler) Option {
 	return func(o *Options) {
 		o.ConfigDump = r
 	}

ocis-pkg/service/debug/service.go

@@ -8,11 +8,12 @@ import (
 
 	chimiddleware "github.com/go-chi/chi/v5/middleware"
 	"github.com/justinas/alice"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"go.opentelemetry.io/contrib/zpages"
+
 	"github.com/owncloud/ocis/v2/ocis-pkg/cors"
 	"github.com/owncloud/ocis/v2/ocis-pkg/middleware"
 	graphMiddleware "github.com/owncloud/ocis/v2/services/graph/pkg/middleware"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"go.opentelemetry.io/contrib/zpages"
 )
 
 // NewService initializes a new debug service.
@@ -28,11 +29,16 @@ func NewService(opts ...Option) *http.Server {
 		promhttp.Handler(),
 	))
 
-	mux.HandleFunc("/healthz", dopts.Health)
-	mux.HandleFunc("/readyz", dopts.Ready)
+	if dopts.Health != nil {
+		mux.Handle("/healthz", dopts.Health)
+	}
+
+	if dopts.Ready != nil {
+		mux.Handle("/readyz", dopts.Ready)
+	}
 
 	if dopts.ConfigDump != nil {
-		mux.HandleFunc("/config", dopts.ConfigDump)
+		mux.Handle("/config", dopts.ConfigDump)
 	}
 
 	if dopts.Pprof {

services/activitylog/pkg/command/server.go

@@ -9,10 +9,11 @@ import (
 	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/cs3org/reva/v2/pkg/store"
 	"github.com/oklog/run"
+	"github.com/urfave/cli/v2"
+	microstore "go-micro.dev/v4/store"
+
 	"github.com/owncloud/ocis/v2/ocis-pkg/config/configlog"
-	"github.com/owncloud/ocis/v2/ocis-pkg/handlers"
 	"github.com/owncloud/ocis/v2/ocis-pkg/registry"
-	"github.com/owncloud/ocis/v2/ocis-pkg/service/debug"
 	ogrpc "github.com/owncloud/ocis/v2/ocis-pkg/service/grpc"
 	"github.com/owncloud/ocis/v2/ocis-pkg/tracing"
 	"github.com/owncloud/ocis/v2/ocis-pkg/version"
@@ -22,9 +23,8 @@ import (
 	"github.com/owncloud/ocis/v2/services/activitylog/pkg/config/parser"
 	"github.com/owncloud/ocis/v2/services/activitylog/pkg/logging"
 	"github.com/owncloud/ocis/v2/services/activitylog/pkg/metrics"
+	"github.com/owncloud/ocis/v2/services/activitylog/pkg/server/debug"
 	"github.com/owncloud/ocis/v2/services/activitylog/pkg/server/http"
-	"github.com/urfave/cli/v2"
-	microstore "go-micro.dev/v4/store"
 )
 
 var _registeredEvents = []events.Unmarshaller{
@@ -120,7 +120,6 @@ func Server(cfg *config.Config) *cli.Command {
 					http.Context(ctx), // NOTE: not passing this "option" leads to a panic in go-micro
 					http.TraceProvider(tracerProvider),
 					http.Stream(evStream),
-					http.RegisteredEvents(_registeredEvents),
 					http.Store(evStore),
 					http.GatewaySelector(gatewaySelector),
 					http.HistoryClient(hClient),
@@ -146,20 +145,18 @@ func Server(cfg *config.Config) *cli.Command {
 			}
 
 			{
-				server := debug.NewService(
+				debugServer, err := debug.Server(
 					debug.Logger(logger),
-					debug.Name(cfg.Service.Name),
-					debug.Version(version.GetString()),
-					debug.Address(cfg.Debug.Addr),
-					debug.Token(cfg.Debug.Token),
-					debug.Pprof(cfg.Debug.Pprof),
-					debug.Zpages(cfg.Debug.Zpages),
-					debug.Health(handlers.Health),
-					debug.Ready(handlers.Ready),
+					debug.Context(ctx),
+					debug.Config(cfg),
 				)
+				if err != nil {
+					logger.Info().Err(err).Str("server", "debug").Msg("Failed to initialize server")
+					return err
+				}
 
-				gr.Add(server.ListenAndServe, func(_ error) {
-					_ = server.Shutdown(ctx)
+				gr.Add(debugServer.ListenAndServe, func(_ error) {
+					_ = debugServer.Shutdown(ctx)
 					cancel()
 				})
 			}